This invention is concerned with a device which is particularly well suited for use in a farm environment. Large corporate farms are becoming increasingly more prevalent. Also, many farmers are presently acquiring land which is not contiguous to or in the vicinity of their homestead. To assure maximum production yields the modern-day farmer cannot depend on the vagaries of the weather and must exercise some control over the growing conditions affecting his crops. One of the most commonplace controls is that of irrigation.
A well is drilled and an irrigator, which may be energized by a diesel engine supplying electrical power, rotates around the farmer's field to irrigate the crops. While irrigation systems of the past have been automatically controlled by programmable computers, such as shown in U.S. Pat. No. 3,723,753 issued Mar. 27, 1973, they have required the farmer or someone he hires to drive to the field to check system status and to troubleshoot and operate the irrigation system when necessary or desired. Because of the environment, and the expense and complexity of remote control devices, it is not believed that there have been any attempts to remotely control irrigation systems or similar agriculturally oriented functions by telephone.
Patents have issued on telephone controls and other remote controlled appliances. However, telephone remote control devices in the past have taken essentially two forms, one of which is exemplified by patents such as U.S. Pat. No. 3,702,904 entitled "A Signal Counter" wherein the ringing signal of a telephone is utilized and a time consuming complex code of calls and ringing signals is utilized for control purposes. In that type of device there is no assurance that the control instructions have been executed.
Another very complicated form of telephone control is exemplified by U.S. Pat. No. 3,868,640 and No. 3,647,971. In this type of telephone control, such as U.S. Pat. No. 3,868,640, modulator/demodulators (modems) are utilized and complex computer grade commands originated with a digital computer are utilized to read or monitor items such as consumer meters registering the use of utility items such as electricity, gas, water, oil and the like. Similarly, in U.S. Pat. No. 3,647,971 encoding and decoding means transmit and receive as many as 256 tone combinations requiring complex indicating equipment to interpret the transmissions.